Engine Valve Lash - Inspect/Adjust

Size: px

Start display at page:

Download "Engine Valve Lash - Inspect/Adjust"

Curtis Potter
6 years ago
Views:

1 Page 1 of 5 Shutdown SIS Previous Screen Product: TRUCK ENGINE Model: 3126E TRUCK ENGINE CKM Configuration: 3126E Truck Engine CKM00001-UP Testing and Adjusting 3126B and 3126E Truck Engine Media Number -RENR Publication Date -01/02/2006 Date Updated -13/02/2006 Engine Valve Lash - Inspect/Adjust SMCS i To prevent possible injury, do not use the starter to turn the flywheel. Hot engine components can cause burns. Allow additional time for the engine to cool before measuring valve clearance. This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running. Note: Valve lash is measured between the rocker arm and the bridge for the inlet valves. Valve lash is measured between the rocker arm and the valve stem for the exhaust valve. All of the clearance measurements and the adjustments must be made with the engine stopped. The valves must be fully closed. Valve Lash Check An adjustment is not necessary if the measurement of the valve lash is in the acceptable range. Adjust the valve lash while the engine is stopped. The range is specified in Table 1.

2 Page 2 of 5 Table 1 Valve Lash Check (Stopped Engine) 0.38 ± 0.08 mm (0.015 ± TC Compression Stroke TC Exhaust Stroke (1) Firing Order (2) ( 1 ) 360 from TC compression stroke ( 2 ) The No. 1 cylinder is at the front of the engine. If the measurement is not within this range adjustment is necessary. See Testing And Adjusting, "Valve Lash And Valve Bridge Adjustment". Illustration 1 Cylinder and Valve Location g (A) Exhaust valve (B) Inlet valves Valve Lash and Valve Bridge Adjustment

3 Page 3 of 5 Illustration 2 (1) Exhaust rocker arm g (2) Inlet valve bridge (3) Rocker arm adjustment screw locknut for the exhaust rocker arm (4) Rocker arm adjustment screw for the exhaust rocker arm Table 2 Valve Lash Valves Dimension of Gauge Inlet 0.38 ± 0.08 mm (0.015 ± Exhaust Adjust the valve lash while the engine is stopped. 1. Put the No. 1 piston at the top center position on the compression stroke. Refer to Testing and

4 Page 4 of 5 Adjusting, "Finding Top Center Position for No. 1 Piston". Table 3 TC Compression Stroke Valve lash 0.38 ± 0.08 mm (0.015 ± Cylinders Adjust the valve lash according to Table 3. a. Lightly tap the rocker arm at the top of the adjustment screw with a soft mallet. This will ensure that the lifter roller seats against the camshaft's base circle. b. Loosen the adjustment locknut. c. Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge. d. Tighten the adjustment locknut to a torque of 30 ± 7 N m (22 ± 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut. 3. Remove the timing bolt and turn the flywheel by 360 degrees in the direction of engine rotation. This will put the No. 6 piston at the top center position on the compression stroke. Install the timing bolt in the flywheel. Table 4 TC Exhaust Stroke (3) Valve lash 0.38 ± 0.08 mm (0.015 ± Cylinders ( 3 ) Position for No. 1 cylinder 4. Adjust the valve lash according to Table 4. a. Lightly tap the rocker arm at the top of the adjustment screw with a soft mallet. This will ensure that the lifter roller seats against the camshaft's base circle.

5 Page 5 of 5 b. Loosen the adjustment locknut. c. Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge. d. Tighten the adjustment locknut to a torque of 30 ± 7 N m (22 ± 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut. 5. Remove the timing bolt from the flywheel after all adjustments to the valve lash have been made. Reinstall the timing cover. Copyright Caterpillar Inc. All Rights Reserved. Private Network For SIS Licensees. Wed Sep 22 09:53:31 CDT 2010

Engine Valve Lash - Inspect/Adjust

Engine Valve Lash - Inspect/Adjust https://siswecat.com/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/s... Page 1 of 5 Shutdown SIS Previous Screen Product: TRUCK ENGINE Model: C15 TRUCK ENGINE BXS Configuration: C15 On-highway